Taper in cylinder bores
TECH Fanatic
Joined: Jun 2002
Posts: 1,979
Likes: 3
From: Upstate NY
Originally Posted by Race-Prep
The "NASCAR BAR" is really nothing more than a lever attached to the hone head that allows the stroke to be held slower at that point to allow the user to adjust the size in that specific area to get the cylinder straight, really it is just a way to "cheat" the machine into making it hone right. Our Sunnen CV616 is able to vary the cutting pressure to open up tight spots in the bore and I prefer this method as it does not vary the cross hatch pattern. As for the bore concentricity and taper, I would NEVER run a performance engine with more than .0002" (2 tenths) out of round and taper, and we usually keep them less than that with the Torque Plate installed. The Cup teams and Pro-Stockers even go so far as to have the cylinder "Hot Honed" or honed with the block heated to operating temperature, this gets as close to real running conditions as possible. There is a lot of technology just in the honing process and many diffrent honing procedures for different rings.
-Bryan
-Bryan
Sunnen's circulating hot honing system, while messy and fun to acurately measure size during the process, has merit. I thought that it might be used as a development tool to redesign block castings so that they distort less as they go from room to operating temps. After looking closely at the Toyota Craftsman Truck block a couple years ago, it wouldn't surprise me if they did something like that. There were a lot of nice touches cast into that block.
AFAIK, if you want differing amount of oil retention in different parts of the bore, laser structuring and then final honing is probably the most consistent way to achieve this. IMO, folks that don't check their honing with a profilometer on every bore (in a race engine anyway) may be leaving power on the table. Eyeballs and fingernails just aren't good enough.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Originally Posted by Old SStroker
Tell me about it. I'm not familiar with the term.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Originally Posted by Old SStroker
Sunnen's circulating hot honing system, while messy and fun to acurately measure size during the process, has merit. I thought that it might be used as a development tool to redesign block castings so that they distort less as they go from room to operating temps. After looking closely at the Toyota Craftsman Truck block a couple years ago, it wouldn't surprise me if they did something like that. There were a lot of nice touches cast into that block.
AFAIK, if you want differing amount of oil retention in different parts of the bore, laser structuring and then final honing is probably the most consistent way to achieve this. IMO, folks that don't check their honing with a profilometer on every bore (in a race engine anyway) may be leaving power on the table. Eyeballs and fingernails just aren't good enough.
AFAIK, if you want differing amount of oil retention in different parts of the bore, laser structuring and then final honing is probably the most consistent way to achieve this. IMO, folks that don't check their honing with a profilometer on every bore (in a race engine anyway) may be leaving power on the table. Eyeballs and fingernails just aren't good enough.
Suspended Sponsor
Joined: Oct 2004
Posts: 371
Likes: 0
From: Just outside of Palm Springs Ca.
I know exactly what you mean, the old dry sleeves that we had to do back then were very...um, shall I say ductile? LOL. The hone took a very good machinist to get those straight, not to mention the fact that if they moved that much with the hone head, imagine what was happening when you crank like 600HP through it! Glad to see the changes in the market lately!
-Bryan
-Bryan
